What's the Best Smartphone in an Emergency?

What phone is better to have on you during an emergency, an iPhone, Android or a Blackberry? Well, it sort of depends.

There are three things to think about when calamity strikes: can you make a phone call? Can you keep tabs on the latest information? And will your battery last?

There's no one type of phone that's the best at all three, but let me walk you through some of the tradeoffs.

First, making a phone call. Research in Motion's BlackBerry devices are great at this. Pretty much universally, my BlackBerry can get a signal where my iPhone just cannot. If you're in the type of emergency where you're stuck in one spot and can't roam around to get a signal, the Blackberry proves helpful. (Read More: Apple Offers a Charge to New Yorkers After Storm )

On the other hand, if you can walk a couple blocks in search of a better signal, that might make things easier.

Next, apps. Why do apps matter? In emergencies, social media is the new email.

Then there's the battery. If you can plan ahead, you can get an external charger for iPhones and Android devices that uses AA batteries. Something like this Energizer charger.

You can't, however, swap out the battery in an iPhone, but an external charger is arguably better because you can keep your phone running longer that just changing the battery.

So, bottom line? If a completely unexpected disaster hits, it's nice to have a BlackBerry — or a plain old feature phone. But if you've got any time to plan, to get some accessories, iPhone and Android really have significant advantages.